Last Tuesday, after our weekly Hamlet net, LARC President, Chuck, K0ITP asked if I had played with LinBPQ. I hadn’t but was interested. So I told Chuck that I would try to get it working and we could exchange noted.
Challenge accepted.
So began another deep dive into another interesting facet of amateur radio. I wanted to start from the beginning rather than jumping head-first into the middle of something. Fortunately, I already researched and wrote an article on packet radio and understood that at its most basic, packet radio is concerned with sending data (at least as far as amateur radio is concerned) over the airwaves using audible sound as the information that is sent over (using rf as the medium since it travels faster and doesn’t lose signal strength as fast as audible sound does but we know this already).
I searched the internet to find out more of what BPQ was used for and came up with several sites including a packet-radio.net website https://packet-radio.net/bpq32/
Unfortunately, this and other sites didn’t tell you what BPQ (or commonly BPQ32) was – only how to use it. I was looking for a better description of its capabilities other than it’s some sort of packet radio BBS. I couldn’t find information on if its features overlapped with some other software, or of there was other software that did the same thing this did or not.
Another issue with searching on the internet was that most of the information I found was nearly 10 years old. Now, rf hasn’t changed much during that time but I was really afraid of dealing with outdated information leading me to think I failed at doing something when I was really just on the wrong frequency or something else elementary.
I also searched YouTube for videos but really the only good, recent ones I came up with dealt with softwares like Direwolf and Xastir and the like. It seems like I was supposed to learn from the middle-out. It also seemed that many examples were using radios without built-in sound cards and that I needed a hardware TNC and a USB sound card. Fooey! My ICOM’s have build in sound cards and DireWolf’s site includes information about it being better than hardware TNC’s in general.
So I decided to take a step back and take some baby steps. I planned on learning in order of easiest to most involved. The general plan was to focus on APRS packets first and then progress towards BPQ and related later on. I know there are a few ham entities around here like BCARES that do BBSes so I would try to access their systems first prior to progressing into trying to create a station myself that K0ITP could access, which would be the pinnacle of success.
Step 1: Tune to 144.390 FM and ensure I could hear packets
This was easy. I tuned my ICOM 7100 to 144.390, FM, and opened up the squelch so I could hear static with lots of packet activity.
Step 2: Use the “Packet” app (purchased for the LARC SSTV Foxhunt) and see if it can decode packets (to confirm my attic antenna + ICOM 7100 could receive well enough)
Again, easy enough. Here is a photo of my iPhone behind the speaker that is emitting sounds like CompuServe in the 1980’s.
Step 3: Confirm that my Baofeng APRS cable + Baofeng + APRSDroid can decode packets. Eventually, my packet solution will be a Baofeng + APRS (ie packet) cable + Raspberry Pi + some combination of DireWolf/LinBPQ32/whatever (i.e. probably not my desktop ICOM 7100) so I really want this portable combination to work.
This was a little more involved. My android device only had a USB-C input and no headphone/microphone 3.5mm jack! Luckily I found the box it came in and it had a USB-C to 3.5mm converter. I attached my attic antenna to the Baofeng, listened for APRS packets, and then plugged in the speaker/mic jack on the side of the radio. Then I started up APRS droid and configured its settings to only do AFSK through the mic/headphones. Just to be sure, I turned off WIFI so my Android device/APRSDroid couldn’t inadvertently use the internet/APRIS-IS and make me falsely think it was working correctly (correctly at this point is RF-only – no internet…yet.).
I wasn’t having much luck with the combination but I know it worked maybe a year, previously. I turned off the squelch and turned off the battery saving mode so that the radio was always listening and not possibly missing the initial tones. Still no dice compared to my iPhone decoding packets from my ICOM 7100’s speaker, so I gave up to try later.
Later on, there were some more frequent and stronger signals, so I tried again except this time I unplugged the APRS cable and put my iPhone in front of the Baofeng to see if the Packet app could decode the packets via the HT’s speaker. Ok now it was working! So I left the volume of the Baofeng as-is and plugged in the APRS cable and fired up APRSDroid.
Success! The baofeng HT + APRS cable + APRS Droid was able to decode packets!
Step 4: Report position via Baofeng + APRS cable + APRSDroid
I tried to turn on the VOX so that I (well APRSDroid) could automatically send positions every once in a while thru the HT. That didn’t seem to work at VOX level 5 all the way down to level 1. Maybe a setting in APRS droid or volume control or something?
Then I pressed the PTT and pressed the “send position” button in APRSDroid and transmitted a position packet. A few seconds later my position showed up on the aprs.fi website! So in theory, I can send and receive APRS packets with my RF-only station.
I also noticed today that there are many weather stations on the https://aprs.fi/#!lat=39.99700&lng=-105.09740 website map with the current weather info. Pretty cool!
OK! That about wraps it up for this set of experiments. Looks like my equipment can at least send and receive APRS packets. In the next article, we will move over to the Raspberry Pi and play around with DireWolf and other packet software towards our ultimate packet radio station.
73,
ae0rs
